diff options
Diffstat (limited to 'net/netfilter/xt_IDLETIMER.c')
-rw-r--r-- | net/netfilter/xt_IDLETIMER.c | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c new file mode 100644 index 000000000..0f8bb0bf5 --- /dev/null +++ b/net/netfilter/xt_IDLETIMER.c @@ -0,0 +1,542 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/net/netfilter/xt_IDLETIMER.c + * + * Netfilter module to trigger a timer when packet matches. + * After timer expires a kevent will be sent. + * + * Copyright (C) 2004, 2010 Nokia Corporation + * Written by Timo Teras <ext-timo.teras@nokia.com> + * + * Converted to x_tables and reworked for upstream inclusion + * by Luciano Coelho <luciano.coelho@nokia.com> + * + * Contact: Luciano Coelho <luciano.coelho@nokia.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/timer.h> +#include <linux/alarmtimer.h> +#include <linux/list.h> +#include <linux/mutex.h> +#include <linux/netfilter.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_IDLETIMER.h> +#include <linux/kdev_t.h> +#include <linux/kobject.h> +#include <linux/workqueue.h> +#include <linux/sysfs.h> + +struct idletimer_tg { + struct list_head entry; + struct alarm alarm; + struct timer_list timer; + struct work_struct work; + + struct kobject *kobj; + struct device_attribute attr; + + unsigned int refcnt; + u8 timer_type; +}; + +static LIST_HEAD(idletimer_tg_list); +static DEFINE_MUTEX(list_mutex); + +static struct kobject *idletimer_tg_kobj; + +static +struct idletimer_tg *__idletimer_tg_find_by_label(const char *label) +{ + struct idletimer_tg *entry; + + list_for_each_entry(entry, &idletimer_tg_list, entry) { + if (!strcmp(label, entry->attr.attr.name)) + return entry; + } + + return NULL; +} + +static ssize_t idletimer_tg_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct idletimer_tg *timer; + unsigned long expires = 0; + struct timespec64 ktimespec = {}; + long time_diff = 0; + + mutex_lock(&list_mutex); + + timer = __idletimer_tg_find_by_label(attr->attr.name); + if (timer) { + if (timer->timer_type & XT_IDLETIMER_ALARM) { + ktime_t expires_alarm = alarm_expires_remaining(&timer->alarm); + ktimespec = ktime_to_timespec64(expires_alarm); + time_diff = ktimespec.tv_sec; + } else { + expires = timer->timer.expires; + time_diff = jiffies_to_msecs(expires - jiffies) / 1000; + } + } + + mutex_unlock(&list_mutex); + + if (time_after(expires, jiffies) || ktimespec.tv_sec > 0) + return sysfs_emit(buf, "%ld\n", time_diff); + + return sysfs_emit(buf, "0\n"); +} + +static void idletimer_tg_work(struct work_struct *work) +{ + struct idletimer_tg *timer = container_of(work, struct idletimer_tg, + work); + + sysfs_notify(idletimer_tg_kobj, NULL, timer->attr.attr.name); +} + +static void idletimer_tg_expired(struct timer_list *t) +{ + struct idletimer_tg *timer = from_timer(timer, t, timer); + + pr_debug("timer %s expired\n", timer->attr.attr.name); + + schedule_work(&timer->work); +} + +static enum alarmtimer_restart idletimer_tg_alarmproc(struct alarm *alarm, + ktime_t now) +{ + struct idletimer_tg *timer = alarm->data; + + pr_debug("alarm %s expired\n", timer->attr.attr.name); + schedule_work(&timer->work); + return ALARMTIMER_NORESTART; +} + +static int idletimer_check_sysfs_name(const char *name, unsigned int size) +{ + int ret; + + ret = xt_check_proc_name(name, size); + if (ret < 0) + return ret; + + if (!strcmp(name, "power") || + !strcmp(name, "subsystem") || + !strcmp(name, "uevent")) + return -EINVAL; + + return 0; +} + +static int idletimer_tg_create(struct idletimer_tg_info *info) +{ + int ret; + + info->timer = kzalloc(sizeof(*info->timer), GFP_KERNEL); + if (!info->timer) { + ret = -ENOMEM; + goto out; + } + + ret = idletimer_check_sysfs_name(info->label, sizeof(info->label)); + if (ret < 0) + goto out_free_timer; + + sysfs_attr_init(&info->timer->attr.attr); + info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL); + if (!info->timer->attr.attr.name) { + ret = -ENOMEM; + goto out_free_timer; + } + info->timer->attr.attr.mode = 0444; + info->timer->attr.show = idletimer_tg_show; + + ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr); + if (ret < 0) { + pr_debug("couldn't add file to sysfs"); + goto out_free_attr; + } + + list_add(&info->timer->entry, &idletimer_tg_list); + + timer_setup(&info->timer->timer, idletimer_tg_expired, 0); + info->timer->refcnt = 1; + + INIT_WORK(&info->timer->work, idletimer_tg_work); + + mod_timer(&info->timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + + return 0; + +out_free_attr: + kfree(info->timer->attr.attr.name); +out_free_timer: + kfree(info->timer); +out: + return ret; +} + +static int idletimer_tg_create_v1(struct idletimer_tg_info_v1 *info) +{ + int ret; + + info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL); + if (!info->timer) { + ret = -ENOMEM; + goto out; + } + + ret = idletimer_check_sysfs_name(info->label, sizeof(info->label)); + if (ret < 0) + goto out_free_timer; + + sysfs_attr_init(&info->timer->attr.attr); + info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL); + if (!info->timer->attr.attr.name) { + ret = -ENOMEM; + goto out_free_timer; + } + info->timer->attr.attr.mode = 0444; + info->timer->attr.show = idletimer_tg_show; + + ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr); + if (ret < 0) { + pr_debug("couldn't add file to sysfs"); + goto out_free_attr; + } + + /* notify userspace */ + kobject_uevent(idletimer_tg_kobj,KOBJ_ADD); + + list_add(&info->timer->entry, &idletimer_tg_list); + pr_debug("timer type value is %u", info->timer_type); + info->timer->timer_type = info->timer_type; + info->timer->refcnt = 1; + + INIT_WORK(&info->timer->work, idletimer_tg_work); + + if (info->timer->timer_type & XT_IDLETIMER_ALARM) { + ktime_t tout; + alarm_init(&info->timer->alarm, ALARM_BOOTTIME, + idletimer_tg_alarmproc); + info->timer->alarm.data = info->timer; + tout = ktime_set(info->timeout, 0); + alarm_start_relative(&info->timer->alarm, tout); + } else { + timer_setup(&info->timer->timer, idletimer_tg_expired, 0); + mod_timer(&info->timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + } + + return 0; + +out_free_attr: + kfree(info->timer->attr.attr.name); +out_free_timer: + kfree(info->timer); +out: + return ret; +} + +/* + * The actual xt_tables plugin. + */ +static unsigned int idletimer_tg_target(struct sk_buff *skb, + const struct xt_action_param *par) +{ + const struct idletimer_tg_info *info = par->targinfo; + + pr_debug("resetting timer %s, timeout period %u\n", + info->label, info->timeout); + + mod_timer(&info->timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + + return XT_CONTINUE; +} + +/* + * The actual xt_tables plugin. + */ +static unsigned int idletimer_tg_target_v1(struct sk_buff *skb, + const struct xt_action_param *par) +{ + const struct idletimer_tg_info_v1 *info = par->targinfo; + + pr_debug("resetting timer %s, timeout period %u\n", + info->label, info->timeout); + + if (info->timer->timer_type & XT_IDLETIMER_ALARM) { + ktime_t tout = ktime_set(info->timeout, 0); + alarm_start_relative(&info->timer->alarm, tout); + } else { + mod_timer(&info->timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + } + + return XT_CONTINUE; +} + +static int idletimer_tg_helper(struct idletimer_tg_info *info) +{ + if (info->timeout == 0) { + pr_debug("timeout value is zero\n"); + return -EINVAL; + } + if (info->timeout >= INT_MAX / 1000) { + pr_debug("timeout value is too big\n"); + return -EINVAL; + } + if (info->label[0] == '\0' || + strnlen(info->label, + MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) { + pr_debug("label is empty or not nul-terminated\n"); + return -EINVAL; + } + return 0; +} + + +static int idletimer_tg_checkentry(const struct xt_tgchk_param *par) +{ + struct idletimer_tg_info *info = par->targinfo; + int ret; + + pr_debug("checkentry targinfo%s\n", info->label); + + ret = idletimer_tg_helper(info); + if(ret < 0) + { + pr_debug("checkentry helper return invalid\n"); + return -EINVAL; + } + mutex_lock(&list_mutex); + + info->timer = __idletimer_tg_find_by_label(info->label); + if (info->timer) { + info->timer->refcnt++; + mod_timer(&info->timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + + pr_debug("increased refcnt of timer %s to %u\n", + info->label, info->timer->refcnt); + } else { + ret = idletimer_tg_create(info); + if (ret < 0) { + pr_debug("failed to create timer\n"); + mutex_unlock(&list_mutex); + return ret; + } + } + + mutex_unlock(&list_mutex); + return 0; +} + +static int idletimer_tg_checkentry_v1(const struct xt_tgchk_param *par) +{ + struct idletimer_tg_info_v1 *info = par->targinfo; + int ret; + + pr_debug("checkentry targinfo%s\n", info->label); + + if (info->send_nl_msg) + return -EOPNOTSUPP; + + ret = idletimer_tg_helper((struct idletimer_tg_info *)info); + if(ret < 0) + { + pr_debug("checkentry helper return invalid\n"); + return -EINVAL; + } + + if (info->timer_type > XT_IDLETIMER_ALARM) { + pr_debug("invalid value for timer type\n"); + return -EINVAL; + } + + mutex_lock(&list_mutex); + + info->timer = __idletimer_tg_find_by_label(info->label); + if (info->timer) { + if (info->timer->timer_type != info->timer_type) { + pr_debug("Adding/Replacing rule with same label and different timer type is not allowed\n"); + mutex_unlock(&list_mutex); + return -EINVAL; + } + + info->timer->refcnt++; + if (info->timer_type & XT_IDLETIMER_ALARM) { + /* calculate remaining expiry time */ + ktime_t tout = alarm_expires_remaining(&info->timer->alarm); + struct timespec64 ktimespec = ktime_to_timespec64(tout); + + if (ktimespec.tv_sec > 0) { + pr_debug("time_expiry_remaining %lld\n", + ktimespec.tv_sec); + alarm_start_relative(&info->timer->alarm, tout); + } + } else { + mod_timer(&info->timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + } + pr_debug("increased refcnt of timer %s to %u\n", + info->label, info->timer->refcnt); + } else { + ret = idletimer_tg_create_v1(info); + if (ret < 0) { + pr_debug("failed to create timer\n"); + mutex_unlock(&list_mutex); + return ret; + } + } + + mutex_unlock(&list_mutex); + return 0; +} + +static void idletimer_tg_destroy(const struct xt_tgdtor_param *par) +{ + const struct idletimer_tg_info *info = par->targinfo; + + pr_debug("destroy targinfo %s\n", info->label); + + mutex_lock(&list_mutex); + + if (--info->timer->refcnt == 0) { + pr_debug("deleting timer %s\n", info->label); + + list_del(&info->timer->entry); + del_timer_sync(&info->timer->timer); + cancel_work_sync(&info->timer->work); + sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr); + kfree(info->timer->attr.attr.name); + kfree(info->timer); + } else { + pr_debug("decreased refcnt of timer %s to %u\n", + info->label, info->timer->refcnt); + } + + mutex_unlock(&list_mutex); +} + +static void idletimer_tg_destroy_v1(const struct xt_tgdtor_param *par) +{ + const struct idletimer_tg_info_v1 *info = par->targinfo; + + pr_debug("destroy targinfo %s\n", info->label); + + mutex_lock(&list_mutex); + + if (--info->timer->refcnt == 0) { + pr_debug("deleting timer %s\n", info->label); + + list_del(&info->timer->entry); + if (info->timer->timer_type & XT_IDLETIMER_ALARM) { + alarm_cancel(&info->timer->alarm); + } else { + del_timer_sync(&info->timer->timer); + } + cancel_work_sync(&info->timer->work); + sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr); + kfree(info->timer->attr.attr.name); + kfree(info->timer); + } else { + pr_debug("decreased refcnt of timer %s to %u\n", + info->label, info->timer->refcnt); + } + + mutex_unlock(&list_mutex); +} + + +static struct xt_target idletimer_tg[] __read_mostly = { + { + .name = "IDLETIMER", + .family = NFPROTO_UNSPEC, + .target = idletimer_tg_target, + .targetsize = sizeof(struct idletimer_tg_info), + .usersize = offsetof(struct idletimer_tg_info, timer), + .checkentry = idletimer_tg_checkentry, + .destroy = idletimer_tg_destroy, + .me = THIS_MODULE, + }, + { + .name = "IDLETIMER", + .family = NFPROTO_UNSPEC, + .revision = 1, + .target = idletimer_tg_target_v1, + .targetsize = sizeof(struct idletimer_tg_info_v1), + .usersize = offsetof(struct idletimer_tg_info_v1, timer), + .checkentry = idletimer_tg_checkentry_v1, + .destroy = idletimer_tg_destroy_v1, + .me = THIS_MODULE, + }, + + +}; + +static struct class *idletimer_tg_class; + +static struct device *idletimer_tg_device; + +static int __init idletimer_tg_init(void) +{ + int err; + + idletimer_tg_class = class_create(THIS_MODULE, "xt_idletimer"); + err = PTR_ERR(idletimer_tg_class); + if (IS_ERR(idletimer_tg_class)) { + pr_debug("couldn't register device class\n"); + goto out; + } + + idletimer_tg_device = device_create(idletimer_tg_class, NULL, + MKDEV(0, 0), NULL, "timers"); + err = PTR_ERR(idletimer_tg_device); + if (IS_ERR(idletimer_tg_device)) { + pr_debug("couldn't register system device\n"); + goto out_class; + } + + idletimer_tg_kobj = &idletimer_tg_device->kobj; + + err = xt_register_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg)); + + if (err < 0) { + pr_debug("couldn't register xt target\n"); + goto out_dev; + } + + return 0; +out_dev: + device_destroy(idletimer_tg_class, MKDEV(0, 0)); +out_class: + class_destroy(idletimer_tg_class); +out: + return err; +} + +static void __exit idletimer_tg_exit(void) +{ + xt_unregister_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg)); + + device_destroy(idletimer_tg_class, MKDEV(0, 0)); + class_destroy(idletimer_tg_class); +} + +module_init(idletimer_tg_init); +module_exit(idletimer_tg_exit); + +MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>"); +MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>"); +MODULE_DESCRIPTION("Xtables: idle time monitor"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("ipt_IDLETIMER"); +MODULE_ALIAS("ip6t_IDLETIMER"); |